Impact of deforestation in the Amazon basin on cloud climatology
- Jingfeng Wanga,1,
- Frédéric J. F. Chagnona,
- Earle R. Williamsa,
- Alan K. Bettsb,
- Nilton O. Rennoc,
- Luiz A. T. Machadod,
- Gautam Bishta,
- Ryan Knoxa and
- Rafael L. Brase
- aDepartment of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139;
- bAtmospheric Research, Pittsford, VT 05763;
- cDepartment of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48109;
- dSatellites and Environmental Division, Instituto Nacional Presquisa Espaciais, CEP 12630-000, Cachoeira Paulista, São Paolo, Brazil; and
- eHenry Samueli School of Engineering, University of California, Irvine, CA 92697
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Edited by Robert E. Dickinson, Georgia Institute of Technology, Atlanta, GA, and approved January 9, 2009 (received for review October 10, 2008)
Abstract
Shallow clouds are prone to appear over deforested surfaces whereas deep clouds, much less frequent than shallow clouds, favor forested surfaces. Simultaneous atmospheric soundings at forest and pasture sites during the Rondonian Boundary Layer Experiment (RBLE-3) elucidate the physical mechanisms responsible for the observed correlation between clouds and land cover. We demonstrate that the atmospheric boundary layer over the forested areas is more unstable and characterized by larger values of the convective available potential energy (CAPE) due to greater humidity than that which is found over the deforested area. The shallow convection over the deforested areas is relatively more active than the deep convection over the forested areas. This greater activity results from a stronger lifting mechanism caused by mesoscale circulations driven by deforestation-induced heterogeneities in land cover.
Footnotes
- 1To whom correspondence should be addressed. E-mail: jfwang{at}mit.edu
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Author contributions: J.W. and R.L.B. designed research; J.W. and F.J.F.C. performed research; A.K.B., N.O.R., and L.A.T.M. contributed new reagents/analytic tools; J.W., F.J.F.C., L.A.T.M., G.B., and R.K. analyzed data; and J.W., E.R.W., A.K.B., and R.L.B. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
